No abstract

This paper reports the tunability of a two-component gel system based on dendritic l-lysine with a focal point carboxylic acid group and aliphatic diamines. The microscopic structure and macroscopic properties of the gel can be modulated by changing the concentration of the components, altering their molecular structures, or tuning their relative molar ratio. In the latter case, there is a complete change in the morphology of the gel that has a direct impact on its macroscopic properties, specifically its gel-sol transition temperature.

This paper presents the first functionalization of silicon surfaces with well-defined, covalently attached monolayers containing saccharides. Two methods were used to this aim: a thermal method (refluxing in mesitylene) and a recently developed, extremely mild photochemical method (irradiation with 447 nm at room temperature). The results were analyzed by FT-IR and angle-resolved X-ray photoelectron spectroscopy. The use of a two-dimensional detector in ARXPS allows for unparalleled, subnanometer resolution in the determination of the elemental composition of monolayers. Even for monolayers with a total thickness of only approximately 1.5 nm, a clear elemental depth profile can be obtained. Such analyses display for sialic acid-containing monolayers that the mild photochemical attachment does not destroy the (rather fragile) sialic acid moiety and that the sugar is present at the top of the monolayer and thus available for biological interactions.

Osteonecrosis or avascular necrosis (AVN) of the hip is a progressive disease mainly affecting adults in their third, fourth or fifth decade of life. Studies into the natural history of the disease suggest that femoral head collapse occurs within 2-3 yrs with associated degenerative changes and at that stage arthroplasty is the most reliable treatment option. Therefore prevention of femoral head collapse is highly desirable in this young patient group. In early stage disease, before femoral head collapse (Ficat and Arlet stage 1-3) core decompression of the femoral head is currently the most widely used procedure to try to relieve intraosseous pressure in the femoral head and restore blood supply.Greater understanding of the pathogenesis of osteonecrosis has led to research into non-surgical management of early stages of the disease, including pharmacological and biophysical treatments.There may be a reduction in symptoms and evidence of prevention of disease progression following some non-surgical treatments. Further studies are needed, including trials comparing medical management with surgical intervention.

Telegraph noise, i.e., two-level fluctuations (TLF), in the magnetoresistance of Er-doped GaAs has been used to probe the magnetic moment of the small ErAs clusters formed during the molecular beam epitaxy growth process. At high temperatures the TLF are thermally activated but below 350 mK tunneling of the magnetization dominates.